As we crawl the web, we see bad content inserted on to thousands of hacked sites each day. The number of sites attacked is staggering and the problem is only getting worse. Hackers and spammers target and successfully compromise any sites they can - small personal sites, schools and universities, even multinational corporations. Spam attacks against forums and user content sections of sites, though not as shocking, are even more widespread.

You may have read in an earlier post that we've begun notifying webmasters about new software versions via Webmaster Tools to help protect their sites. Continuing with our effort to provide more useful information to webmasters, we're happy to announce that we'll soon be sending even more notifications to the Message Center.

Starting this month, we will notify more webmasters of more potential issues we've detected on their websites, including:

These notifications are meant to alert webmasters of potential issues and provide next steps on how to get their sites fixed and back into Google's search results. If it pertains to a hacking or abuse issue, the notification will point to example URLs exhibiting this type of behavior. These notifications will run in parallel with our existing malware notifications.

A notice of suspected hacking, for example, will look like this:

We've been notifying webmasters of suspected hacking for years, but a recent upgrade to our systems will allow us to notify many more site owners that have been hacked. We hope webmasters will find these notifications useful in making sure their sites are clean and secure, ultimately providing a better user experience for their visitors. In the future, we may extend this effort even further to include other types of vulnerabilities or abuse issues.